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A Theoretical Light Scattering Model of Nanoparticle Laser TweezersAccomplishments this reporting period include: 1. derived, programmed, checked, and tested the Mie light scattering theory formulas for the radiation trapping force for both the on-axis and off-axis geometry of the trapping beam plus trapped spherical particle; 2. verified that the computed radiation trapping force for a freely propagating focused Gaussian laser beam incident on a spherical particle agrees with previous published calculations; 3. compared the small particle size and large particle size limits of the Mie calculation with the results of Rayleigh scattering theory and ray scattering theory, respectively and verified that the comparison is correct for Rayleigh scattering theory but found that ray theory omits an important light scattering effect included in the Mie theory treatment; 4. generalized the calculation of the radiation trapping force on a spherical particle in the on-axis geometry from a freely propagating focused Gaussian laser beam to the realistic situation of a Gaussian beam truncated and focused by a high numerical aperture oil-immersion microscope objective lens and aberrated by the interface between the microscope cover slip and the liquid-filled sample volume; and 5. compared the calculated radiation trapping force for this geometry with the results of previously published experiments and found that the agreement is better than when using previously developed theories.
Document ID
20030066422
Acquisition Source
Headquarters
Document Type
Contractor or Grantee Report
Authors
Lock, James A.
(Cleveland State Univ. Cleveland, OH, United States)
Date Acquired
August 21, 2013
Publication Date
June 18, 2003
Subject Category
Lasers And Masers
Funding Number(s)
CONTRACT_GRANT: NAG3-2774
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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